What happened
On 10 February 2010, at 16:19, a serious runway incursion occurred at Rovaniemi aerodrome. A Finnish Air Force Learjet 35A/S (call sign M21) was cleared for takeoff from runway 21. Simultaneously, a maintenance vehicle, identified by the call sign HARJA 3, was positioned at the end of runway 03 performing runway cleaning operations.
The air traffic controller, while observing the aircraft's takeoff roll, realized that the vehicle was still on the runway and immediately instructed HARJA 3 to veer to the left. Due to the undulating profile of the runway, the flight crew of M2 21 did not observe the vehicle. At the moment the aircraft became airborne, it was estimated to be at an altitude of approximately 100 meters, passing over the vehicle, which was at a horizontal distance of at least 500 meters. The crew only became aware of the incident after landing in Jyväskylä.
The investigation
The investigation established that the controller had recently been qualified for the Rovaniemi position, having held the position for only about two weeks. The controller had inadvertently issued the takeoff clearance without verifying that the runway was clear, specifically overlooking a magnetic marker on the controller's desk indicating the presence of the maintenance vehicle.
Investigators also examined the operational environment, noting that the controller was working alone and that air traffic, primarily consisting of helicopters, was heavier than usual. The investigation also looked into the visibility from the tower, which was unobstructed by weather, and the communication protocols between ground personnel and air traffic control.
Findings
- The primary cause of the incident was the inadvertent issuance of takeoff clearance without confirming the runway was clear of obstructions.
- The air traffic controller's limited operational experience and the fact that they were working alone were significant contributing factors.
- Increased traffic volume, specifically a higher-than-normal density of helicopter operations, added to the controller's workload.
- The physical topography of the runway prevented the aircraft crew from visually detecting the maintenance vehicle during the takeoff roll.
- There was a lack of emphasis in training for maintenance personnel regarding the importance of specific English aviation phraseology used in VHF communications.
Safety action
- Finavia Oyj should review the requirements for air traffic controller ratings, specifically considering the impact of limited work experience.
- Continued development and implementation of an electronic ground vehicle positioning and warning system for the control tower is recommended.
- Training programs for maintenance personnel should emphasize the significance of key English phrases used in aviation radio communications.
- Ground movement radiotelephony instructions should be supplemented with specific procedures for emergency runway clearance.